In order to store large amounts of data such as a high image quality video, there has recently been a demand for a large-capacity information recording medium. A high-density information recording medium that is expected to satisfy such a demand is exemplified by a super-resolution medium (i) in which content information is recorded by a pit group including a pit that is shorter in length than an optical system resolution limit and (ii) which is played back by higher playback power than normal.
In order to ensure compatibility between information recording mediums, an information recording medium is generally provided with not only a data region (i.e., a region in which content is recorded) but also a medium information region (i.e., a region in which information for identifying a type of an information recording medium is recorded). By playing back the medium information region, a playback device reads information that is necessary for playing back the data region. Subsequently, the playback device plays back the data region.
As in the case of a normal medium (i.e., a non-super-resolution medium), a super-resolution medium is also provided with a medium information region and a data region that are identical in recording density. Against a background of this, there have been proposed various methods for responding to an increase in total number of clusters due to an increase in recording density.
Patent Literature 1 discloses a method for recording address information in each of a medium information region and a data region of a super-resolution medium by use of an address data format which differs from that of a normal medium. (b) of FIG. 15 illustrates an address data format of a super-resolution medium disclosed in Patent Literature 1. (a) of FIG. 15 illustrates an address data format of a normal medium disclosed in Patent Literature 1.